I have a trailboss 350l I think it is a 1990 or 1991. Has only 300 miles on it. Very mild use for plowing driveway. This ATV sat for years unused. When I got it from the original owner I replaced the spark plug, drained the gas, cleaned the carb (twice) and it still runs like crap. I also adjusted the throttle freeplay in order to get it to idle. The rubber connections between the carb/airbox and carb/manifold seem to be fine with no cracks or holes.

It will idle fine but under throttle it just kind of pops and has very little power. It seems to improve (altho very slightly) at full throttle.

I drive a race car and it almost sounds like a rev limiter? Would this ATV have one?

Any ideas of what I can look at next?